Journal cover Journal topic
Solid Earth An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 2.921
IF2.921
IF 5-year value: 3.087
IF 5-year
3.087
CiteScore value: 4.8
CiteScore
4.8
SNIP value: 1.314
SNIP1.314
IPP value: 2.87
IPP2.87
SJR value: 0.993
SJR0.993
Scimago H <br class='widget-line-break'>index value: 38
Scimago H
index
38
h5-index value: 36
h5-index36
Preprints
https://doi.org/10.5194/se-2020-175
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/se-2020-175
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

  19 Oct 2020

19 Oct 2020

Review status
This preprint is currently under review for the journal SE.

Kinematics of subduction in the Ibero-Armorican arc constrained by 3D microstructural analysis of garnet and pseudomorphed lawsonite porphyroblasts from Ile de Groix (Variscan belt)

Domingo Aerden1,2, Mohammad Sayab4, Aidan Forde3, and Alejandro Ruiz-Fuentes1 Domingo Aerden et al.
  • 1Departamento de Geodinámica, Universidad de Granada, Spain
  • 2Instituto Andaluz de Ciencias de la Tierra, CSIC/Universidad de Granada, Spain
  • 3Saorgus Energy Ltd, Kerry, Ireland
  • 4Geological Survey of Finland, Espoo, Finland

Abstract. The small island of Groix in southern Brittany, France, is well known for its excellent outcrops of Variscan blueschists, eclogites and garnetiferous micaschists that define a Late-Devonian suture between Gondwana and Armorica. The kinematics of polyphase deformation in these rocks is reconstructed based on 3D microstructural analysis of inclusion trails in garnet- and pseudomorphed lawsonite porphyroblasts using multiple, differently oriented thin sections of single samples and X-ray tomography. Three sets of inclusion trails striking NE-SW, NNW-SSE and WNW-ESE are interpreted to witness a succession of different crustal shortening directions orthogonal to these trends. The curvature sense of sigmoidal- and spiral-shaped inclusion trails of the youngest set is shown to be consistent with southward thrusting or northward subduction of Gondwana under Armorica, provided that these microstructures developed by overgrowth of actively forming crenulations instead of the previously envisaged 'snowball' mechanism. The latter predicts an opposite thrusting direction which is at odds with the regional tectono-metamorphic zonation in the Ibero-Armorican Arc. Strongly non-cylindrical folds locally found on Ile de Groix are reinterpreted as fold-interference structures instead of having formed by progressive shearing. Six additional samples of lower-grade footwall units of the Groix ophiolite were also studied. The oldest inclusion trails in these rocks have similar trends as the youngest one in Ile de Groix. Our new inclusion-trail data for southern Brittany bear a strong resemblance with those documented previously in the north-western Iberian Massif and suggest about 20° anticlockwise rotation of Iberia during the early Cretaceous opening of the Gulf of Biscay.

Domingo Aerden et al.

Interactive discussion

Status: final response (author comments only)
Status: final response (author comments only)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Login for Authors/Topical Editors] [Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement

Domingo Aerden et al.

Domingo Aerden et al.

Viewed

Total article views: 331 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
271 57 3 331 1 0
  • HTML: 271
  • PDF: 57
  • XML: 3
  • Total: 331
  • BibTeX: 1
  • EndNote: 0
Views and downloads (calculated since 19 Oct 2020)
Cumulative views and downloads (calculated since 19 Oct 2020)

Viewed (geographical distribution)

Total article views: 298 (including HTML, PDF, and XML) Thereof 297 with geography defined and 1 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Saved

No saved metrics found.

Discussed

No discussed metrics found.
Latest update: 04 Dec 2020
Publications Copernicus
Download
Citation